cannot use bytes as filename

[petaflot]

  File "[...]/pylatex/base_classes/latex_object.py", line 168, in generate_tex
    with open(filepath + '.tex', 'w', encoding='utf-8') as newf:
              ~~~~~~~~~^~~~~~~~
TypeError: can't concat str to bytes

I suppose this says it all..

[SG420]

This isn't a pylatex issue, you're trying to concatanate filepath, which presumably isn't a string, to '.tex', which is a string. You need to first cast filepath to a str

[petaflot]

I disagree. not all bytestrings can be casted to str. some filesystems (ie. xfs, zfs) accept bytes that cannot be encoded in human-readable strings (ie. ascii, utf)

the code should read sth like

try:
    with open(filepath + '.tex', 'w', encoding='utf-8') as newf:
       ...
except TypeError:
    with open(filepath + b'.tex', 'w', encoding='utf-8') as newf:
       ...

[petaflot]

better still:

try:
    full_filename = filepath + '.tex'
except TypeError:
    full_filename = filepath + b'.tex'
with open(full_filename, 'w', encoding='utf-8') as newf:
    ...

you get the point. one can also check on the type of filepath. however you prefer, there are a number of somewhat equivalent way to do it.